Method of allocating resources in a wireless network

ABSTRACT

A device for allocating a channel resource in a wireless network includes a Media Access Control (MAC)/MAC Layer Management Entity (MLME) sublayer and the MAC/MLME sublayer receives a primitive requesting to transmit a message for requesting the channel resource from an upper layer; transmits the message for requesting the channel resource to a coordinator, wherein the message for requesting the channel resource includes information about a duration of the channel resource; and receives channel resource allocation information for allocating the channel resource from a MAC/MLME sublayer of the coordinator, the channel resource allocation information including information about a duration of the allocated channel resource, wherein the device transmits a first message to a second device during the channel resource allocated based upon the channel resource allocation information, and receives a second message from the second device in response to the first message during the allocated channel resource.

TECHNICAL FIELD

The present invention relates to a wireless network, and moreparticularly, to a method of allocating instant channel resources in awireless network.

BACKGROUND ART

Recently, a number of kinds of networks have been developed andimplemented in a real life owing to the development of communication,computer and networking technology. A large-scaled network, such as wireor wireless Internet, which connects the whole world, exists while asmall-scaled wire or wireless network exists, which connects digitaldevices in limited places such as general homes or companies. With thedevelopment of various types of networks, various interfacing techniqueshave been also developed, which connect networks or devices with eachother to perform communication between them.

FIG. 1 illustrates an example of a wireless video area network (WVAN)which is a kind of a wireless private access network (WPAN). The WVAN isa network configured between digital devices within a limited place,such as home, within 10 m to ensure throughput of 4.5 Gbps or greater ata bandwidth of about 7 GHz, thereby supporting non-compressiontransmission of 1080 p A/V streams.

FIG. 2 illustrates an example of a structure of superframes used in theWVAN. Referring to FIG. 2, each superframe includes a beacon region towhich a beacon is transmitted, a reserved region allocated to a randomdevice by a coordinator in accordance with a request of devices, and anunreserved region where data are transmitted and received between thecoordinator and a device or between devices in accordance with acontention based mode without being allocated by the coordinator,wherein each of the regions undergoes time division. The beacon includestiming allocation information in a corresponding superframe andmanagement and control information of WVAN.

The reserved region is used to allow a device, to which a channel timeis allocated by the coordinator in accordance with a channel timeallocation request of the device, to transmit data to another device.Commands, data streams, asynchronous data, etc. can be transmittedthrough the reserved region. The unreserved region can be used totransmit control information, MAC command or asynchronous data betweenthe coordinator and the device or between the devices. To avoid datacollision between the devices in the unreserved region, a carrier sensemultiple access (CSMA) mode or a slotted Aloha mode can be used. Thelength and the number of reserved regions and unreserved regions in eachsuperframe may depend on superframe and may be controlled by thecoordinator.

A specific device in the WVAN transmits a bandwidth request command tothe coordinator so that the device can be allocated with channelresources for data transmission. The coordinator checks whether thereare channel resources to be allocated to the device. If there arechannel resources to be allocated to the device, the coordinatorallocates the requested channel resources to the device. At this time,information of the channel resources allocated to the device, i.e.,timing allocation information is forwarded to the devices within theWVAN through a beacon which will be transmitted later.

Accordingly, in order that a random device is allocated with channelresources by requesting the coordinator of the channel resources andtransmits data by using the allocated channel resources, the deviceshould wait for the time to receive at least next beacon. This method ofallocating channel resources may have a problem when instant datatransmission is required. In other words, if message exchange betweentwo devices is instantly required, for example, if there is a previouslyset timing constraint to receive a response message to a messagetransmitted from a specific device to another device, a problem occursin that the method of allocating channel resources according to therelated art cannot fulfill the timing constraint. In this case, messageexchange through a contention interval without allocation of channelresources may be considered. However, since the contention based messageexchange may cause collision between devices, a problem occurs in thatit is impossible to ensure certainty in message transmission andreception.

DISCLOSURE OF THE INVENTION

Accordingly, the present invention is directed to a method of allocatingchannel resources in a wireless network, which substantially obviatesone or more problems due to limitations and disadvantages of the relatedart.

An object of the present invention is to provide a method of allocatinginstant channel resources if necessary in a state that channel resourcesare already allocated.

Another object of the present invention is to provide a method ofallocating channel resources in a wireless network, in which delay inmessage transmission between a wire network and a wireless network orbetween two devices can be avoided, whereby desirable communication canbe performed.

To achieve these objects and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described herein, amethod of allocating instant channel resources in a wireless networkincludes receiving channel resource allocation information of a specificsuperframe, which includes timing information of at least one reservedduration and at least one unreserved duration, from a coordinator of thewireless network, requesting the coordinator to allocate instant channelresources for an unreserved duration of the specific superframeidentified by the channel resource allocation information, and receivingallocation information of the instant channel resources, which areallocated within the unreserved duration of the specific superframe,from the coordinator.

In another aspect of the present invention, a method of allocatinginstant channel resources in a coordinator of a wireless networkincludes broadcasting channel resource allocation information of aspecific superframe to the wireless network, receiving a first messagerequesting allocation of instant channel resources for an unreservedduration of the specific superframe from a specific device of thewireless network, and broadcasting a second message to the wirelessnetwork, the second message announcing allocation of the instant channelresources within the unreserved duration of the specific superframe.

In still another aspect of the present invention, a method of allocatinginstant channel resources in a coordinator of a wireless networkincludes receiving a first message requesting channel resources fortransmission or reception of data from at least one device, broadcastingchannel resource allocation information of a specific superframe, whichis scheduled considering request of channel resources from the at leastone device, to the wireless network through a beacon, receiving a secondmessage from a specific device of the wireless network, the secondmessage requesting allocation of instant channel resources for anunreserved duration of the specific superframe, and broadcasting a thirdmessage to the wireless network, the third message announcing allocationof the instant channel resources within the unreserved duration of thespecific superframe.

Preferably, the wireless network is a wireless video area network(WVAN), and the channel resource allocation information is received bybeing included in a beacon. The instant channel resource allocationrequest can be performed through LRP channel of HRP channel and LRPchannel which are used in the WVAN. Also, allocation information of theinstant channel resources can be received through the LRP channel.

Preferably, the instant channel resources include a first channelresource for transmitting a specific message and a second channelresource for receiving a response message to the specific message. Thefirst channel resource and the second channel resource are successivelylocated or spaced apart from each other at a predetermined interval.

In further still another aspect of the present invention, a method ofallocating instant channel resources in a wireless network whichperforms using a first channel and a second channel includes receiving abeacon, which includes channel resource allocation information of aspecific superframe, from a coordinator of the wireless network throughthe second channel, transmitting a first message to the coordinatorthrough the second channel, the first message requesting allocation ofinstant channel resources which include a predetermined bandwidth on atleast one of the first channel and the second channel within anunreserved duration of the specific superframe identified by the channelresource allocation information, and receiving allocation information ofinstant channel resources, which are allocated within the unreservedduration of the specific superframe, from the coordinator through thesecond channel.

In further still another aspect of the present invention, a method offorwarding a message in a first interface device connected with a sourcedevice includes receiving a first message from the source device, thefirst message being transmitted to a destination device, allocatinginstant channel resources within a corresponding superframe from acoordinator to receive a response message to the first message from asecond interface device connected with the destination device,transmitting a second message, which includes the first message, to thesecond interface device, receiving a response message to the secondmessage from the second interface device through the allocated instantchannel resources, and transmitting the response message to the firstmessage to the source device.

The allocating step of instant channel resources includes transmittingan instant channel resource allocation request message to thecoordinator of the wireless network, and receiving an instant channelresource allocation announcement message from the coordinator.Preferably, the second message is broadcasted to the wireless network.Preferably, the instant channel resource allocation request message andthe instant channel resource allocation announcement message aretransmitted through the LRP channel. The first message is a consumerelectronics control (CEC) message or a vendor specific data. Theresponse message to the first message is an acknowledgement (ACK)signal.

Preferably, the wireless network is a wireless video area network(WVAN), and the channel resource scheduling information is received bybeing included in a beacon. The instant channel resource allocationrequest and reception of the announcement message can be performedthrough the LRP channel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a configuration example of WPAN;

FIG. 2 illustrates an example of a structure of superframes used inWVAN;

FIG. 3 illustrates a frequency band of HRP channels and LRP channelsused in WVAN;

FIG. 4 illustrates an example of a structure of superframes used inWVAN;

FIG. 5 illustrates an example of a structure of a protocol layerimplemented in a device of WVAN;

FIG. 6 illustrates an example of a structure of superframes according toone embodiment of the present invention;

FIG. 7 illustrates an example of a structure of superframes according toanother embodiment of the present invention;

FIG. 8 is a flow chart illustrating a method of allocating instantchannel resources in accordance with the embodiment of the presentinvention;

FIG. 9 is a schematic view illustrating a system according to theembodiment of the present invention;

FIG. 10A illustrates a data format of a consumer electronics control(CRC) message used in HDMI system;

FIG. 10B illustrates a data format of a header block of a CEC message;

FIG. 11 illustrates a pulse format of each bit constituting a CECmessage;

FIG. 12A illustrates a structure of a system according to the embodimentof the present invention;

FIG. 12B illustrates a structure of another system according to theembodiment of the present invention; and

FIG. 13 is a flow chart illustrating a procedure according to theembodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, structures, operations, and other features of the presentinvention will be understood readily by the embodiments of the presentinvention, examples of which are illustrated in the accompanyingdrawings.

A WVAN is a wireless network configured between digital devices within alimited place, such as home, within 10 m to ensure throughput of 4.5Gbps or greater at a bandwidth of about 7 GHz, thereby supportingnon-compression transmission of 1080 p A/V streams. The WVAN supportsphysical layers, i.e., a high-rate physical (HRP) layer and a low-ratephysical (LRP) layer. The HRP layer is a physical layer which supports adata transmission speed of 1 Gb/s or greater while the LRP layer is aphysical layer which supports a data transmission speed of several Mb/s.The HRP layer is highly directional, and is used to transmit isochronousdata streams, asynchronous data, MAC command, and A/V control datathrough unicast connection. The LRP layer supports a directional oromni-directional mode, and is used to transmit a beacon, asynchronousdata, and MAC command through unicast or broadcast.

FIG. 3 illustrates a frequency band of HRP channels and LRP channelsused in the WVAN. The HRP layer uses four channels of a bandwidth of 2.0GHz in a band of 57-66 GHz, and the LRP uses three channels of abandwidth of 92 MHz. As shown in FIG. 3, the HRP channels and the LRPchannels commonly use a frequency band and are used respectively by atime divisional multiplexing (TDMA) mode.

FIG. 4 illustrates an example of a structure of superframes used in theWVAN. Referring to FIG. 4, each superframe includes a beacon region towhich a beacon is transmitted, a reserved channel time block (CTB)region, and an unreserved channel time block region. The beacon isperiodically transmitted by the coordinator to identify a start part ofeach superframe. The beacon includes scheduled timing information andmanagement and control information of the WVAN. As described above, aspecific device in the WVAN transmits a bandwidth request command to thecoordinator so that the device can be allocated with channel resourcesfor data transmission. The coordinator checks whether there are channelresources to be allocated to the device. If there are channel resourcesto be allocated to the device, the coordinator broadcasts information ofchannel resources allocated to the device, i.e., timing allocationinformation to the devices within the WVAN through a beacon Which willbe transmitted later. Each device can perform data exchange in thenetwork through timing information and management/control informationincluded in the beacon.

The reserved CTB region is used to allow a device, to which a channeltime is allocated by the coordinator in accordance with a channel timeallocation request of the device, to transmit data to another device.Commands, data streams, asynchronous data, etc. can be transmittedthrough the reserved CTB region. If a specific device transmits data toanother device through the reserved CTB region, the HRP channels can beused. If a device which receives data transmits an acknowledgement ornegative acknowledgement (ACK/NACK) signal in response to the receiveddata, the LRP channels can be used.

The unreserved CTB region can be used to transmit control information,MAC command or asynchronous data between the coordinator and the deviceor between the devices. To avoid data collision between the devices inthe unreserved CTB region, a carrier sense multiple access (CSMA) modeor a slotted Aloha mode can be used. In the unreserved CTB region, datacan be transmitted through the LRP channels only. If there are provideda lot of commands or control information to be transmitted, a reservedregion may be set in the LRP channels. The length and the number ofreserved regions and unreserved regions in each superframe may depend onsuperframe and may be controlled by the coordinator. Although not shownin FIG. 4, a contention-based control period (CBCP) may be located nextto the beacon to transmit instant control/management message. The lengthof the CBCP is set so as not to exceed a given threshold valuemMAXCBCPLen.

FIG. 5 illustrates a structure of a protocol layer implemented in adevice of the WVAN. Referring to FIG. 5, a communication module of eachdevice included in the WVAN can be divided into at least two layersdepending on its function. In general, the communication module includesa PHY layer 31 and a MAC layer 30. The communication module includesentities which manage each layer, wherein a MAC layer management entity(MLME) 300 manages the MAC layer and a PHY layer management entity(PLME) 310 manages the PHY layer. Also, the communication module furtherincludes a device management entity (DME) 320 which collects stateinformation of each device and serves as a control interface between ahost and a radio device.

FIG. 6 illustrates an example of a structure of superframes according tothe embodiment of the present invention.

One superframe in the WVAN includes a beacon region, at least onereserved CTB region, and at least one unreserved CTB region. In FIG. 6,a superframe first scheduled by the coordinator includes two unreservedCTB regions (regions ‘a’ and ‘c’) and one reserved CTB region (region‘b’). Detailed timing information of the unreserved CTB regions and thereserved CTB region is included in a beacon located at a starting partof the superframe. Each device within the WVAN transmits or receivesrequired data in accordance with a contention mode through the reservedor unreserved CTB region allocated to itself, as described withreference to FIG. 4, by using information included in the beacon.

If a specific device needs to be instantly allocated with a CTB withinthe superframe, it transmits an instant channel resource request message(INS_CTB_REQ Command) through the region ‘A’ of FIG. 6 to request thecoordinator instant channel resources, i.e., instant CTB within theunreserved CTB region. Table 1 illustrates an example of a format of theinstant channel resource request command. Hereinafter, the terms,‘instant channel resources’ or ‘instant CTB’ are used to identify‘channel resources’ and ‘CTB’ allocated from the coordinator through thebeacon in accordance with a general method. The terms ‘instant channelresources’ or ‘instant CTB’ may be replaced with various terms orgeneral ‘channel resources’ or ‘CTB.’

TABLE 1 Octets: 1 1 1 1 1 2 2 Command Length = Source Target Usage StartInstant ID 7 ID ID Code Limit CTB Duration

In Table 1, a ‘Command ID’ field includes an identifier for identifyingtypes of messages, and a ‘Length’ field includes length information ofthe other part of the instant channel resource request command. A‘Target 1D’ field includes an identifier of a device to which messageswill be transmitted using requested channel resources, and a ‘Source ID’field includes an identifier of a device which will transmit messagesusing requested channel resources. In case of the device which willtransmit messages using the requested channel resources, the ‘Source ID’field may include Broadcast ID before setup. A ‘Usage Code’ fieldincludes an object of reservation of channel resources. A ‘Start Limit’field includes timing constraint information to which channel resourcesshould be allocated. In other words, the channel resources should beallocated within the range of the timing constraint included in the‘Start Limit’ field. The ‘Start Limit’ field may include the fasteststart timing or the latest start timing for allocating instant channelresources which are requested, or information related to both thefastest start timing and the latest start timing. For example, theinstant channel resources allocated in case of the latest start timinginformation should not be allocated to be started at a timing pointlater than that indicated by the start timing information within thesuperframe. An ‘Instant CTB duration’ field includes requested channelresources, i.e., length information of a CTB duration requested formessage transmission.

If there is a request for allocation of the instant channel resources,the coordinator checks whether the instant CTB can be allocated. Ifpossible, the coordinator broadcasts an instant channel resourceallocation announcement command (INS_CTB_ANC Command) from the region‘B’ of FIG. 6 through the WVAN to notify allocation of the instant CTB.Table 2 illustrates an example of a data format of the instant channelresource allocation announcement command.

TABLE 2 Octets: 1 1 1 1 1 2 2 Command Length = Source Target Usage StartInstant ID 7 ID ID Code Offset CTB Duration

In Table 2, a ‘Target ID’ field and a ‘Source ID’ field include the samedetails as those of the ‘Target ID’ field and the ‘Source ID’ field inTable 1. A ‘Start Offset’ field includes start location information of aCTB which is allocated. For example, the ‘Start Offset’ field includesinformation as to whether a start point of an allocated CTB starts froma point indicating how long the point is located away from a specificreference point. An ‘Instant CTB Duration’ field includes information ofchannel resources which are allocated, i.e., duration length informationof an instant CTB which is allocated.

The devices within the WVAN, which have received the instant channelresource allocation message, regard the allocated instant CTB region asthe reserved region. The region ‘C’ of FIG. 6 is an instant CTB regionallocated in accordance with the above procedure, and the specificdevice which has requested allocation of the instant channel resourcescan exchange data with another device through the instant CTB region.Allocation request and allocation announcement of the instant CTB can beperformed through the LRP channels. The instant CTB region includes abandwidth duration corresponding to any one of the LRP and HRP channels.In other words, a specific bandwidth of any one of the LRP channel andthe HRP channel may be used as the instant CTB region, or a specificbandwidth of both of them may be used as the instant CTB region.

FIG. 7 illustrates another example of a structure of superframesaccording to the embodiment of the present invention.

The embodiment of FIG. 7 is different from that of FIG. 6 in that theinstant CTB region is divided into two regions (‘D’ and ‘E’). Forexample, if a specific device within the WVAN instantly should transmita message to another device and receive a response message to thetransmitted message and if there is a time constraint which requiresthat transmission of the message and reception of the response messageshould be performed within a previously set time period, one instant CTBregion can be allocated for transmission of the message, and anotherinstant CTB region can be allocated for reception of the responsemessage. The device which requests allocation of the instant CTB cantransmit the instant channel resource request command to thecoordinator, wherein the instant channel resource request commandincludes information related to an allocation request of the two dividedinstant CTB regions and information related to the minimum and/ormaximum space between the CTB regions in addition to the informationincluded in Table 1.

After receiving the instant channel resource request command, thecoordinator checks whether instant channel resources can be allocated.If possible, the coordinator broadcasts an instant channel resourceallocation announcement command shown in Table 2 through the WVAN. Atthis time, the ‘Start Offset’ field of the instant channel resourceallocation announcement command includes start location information ofeach instant CTB region, and the ‘Instant CTB duration’ field includesduration length information of each instant CTB region.

FIG. 8 is a flow chart illustrating a method of allocating instantchannel resources in accordance with the embodiment of the presentinvention. In the embodiment of FIG. 8, DEV 1 is allocated with instantchannel resources to transmit a first message to DEV 2 and receives asecond message from the DEV 2 in response to the first message.

Referring to FIG. 8, DME of the DEV 1 forwards MLME_INS_CTB.reqprimitive to MAC/MLME of the DEV 1 to command a request for allocationof instant channel resources [S81]. The MAC/MLME of the DEV 1 transmitsan instant channel resource request message (INS_CTB_REQ Command) to thecoordinator to request allocation of the instant channel resources[S82]. An example of the instant channel resource request message is thesame as described with reference to Table 1. MAC/MLME of the coordinatorforwards MLME_INS CTB.ind primitive to DME of the coordinator to notifythe fact that the instant channel resources have been requested from theDEV 1 [S83]. The DME of the coordinator checks channel resources withina corresponding superframe to check whether instant channel resources ofthe DEV 1 can be allocated to the DEV 1 [S84]. If possible, the DME ofthe coordinator forwards MLME_INS_CTB.rsp primitive to the MAC/MLME ofthe coordinator to notify the fact that the instant channel resourcescan be allocated to the DEV 1 [S85].

The MAC/MLME of the coordinator broadcasts an instant channel resourceallocation announcement message (INS_CTB_ANC Command) to the wirelessnetwork to notify the fact that the instant channel resources have beenallocated to the DEV 1 [S86]. An example of the instant channel resourceallocation announcement message is the same as described with referenceto Table 2. The MAC/MLME of the DEV 1 forwards MLME_INS_CTB.cfmprimitive to DME of the DEV 1 to notify the fact that the instantchannel resources have been allocated [S87]. The DME of the DEV 1forwards the MLME_message.req primitive to the MAC/MLME of the DEV 1 tocommand the MAC/MLME of the DEV 1 to transmit the first message to theDEV 2 by using the allocated instant channel resources [S88].

The MAC/MLME of the DEV 1 transmits the first message to the DEV 2 in aunicast or broadcast mode by using the allocated instant channelresources [S89]. The MAC/MLME of the DEV 2 forwards MLME.message.indprimitive to the DME of the DEV 2 to notify reception of the firstmessage [S90]. The DME of the DEV 2 forwards the MLME-message.reqprimitive to the MAC/MLME of the DEV 2 to command the MAC/MLME of theDEV 2 to transmit the second message to the DEV 1 in response to thefirst message [S91]. The MAC/MLME of the DEV 2 transmits the secondmessage to the DEV 1 by using the allocated instant channel resources[S92]. The MAC/MLME of the DEV 1 forwards the MLME.message.ind primitiveto the DME of the DEV 1 to notify reception of the second message [S94].

If a given time constraint is set between the transmission time and thereception time of two primitives or a specific message and a responsemessage to the specific message in accordance with the above method, itis possible to completely ensure a process within the time constraintthrough allocation of the instant channel resources. For example, thetransmission time and the reception time correspond to the time from atransmission timing point of MLME_INS_CTB.req primitive from to areception timing point of MLME_message.ind primitive in the DME of theDEV 1, the time from a transmission timing point of MLME_message.reqprimitive to a reception timing point of MLME_message.ind primitive inthe DME of the DEV 1, or the time from a transmission timing point ofthe first message to a reception timing point of the second message inthe MAC/MLME of the DEV 1.

In FIG. 8, ‘mICRWT’ means a maximum Instant CTB Request Waiting Time,and ‘Instant CTB Duration’ means a duration length of allocated instantchannel resources. The ‘Instant CTB Duration’ is a value set so that theDME of the DEV 1 forwards MLME_message.req primitive to the MAC/MLME ofthe DEV 1 within the instant CTB duration and receives MLME_message.cfmprimitive from the MAC/MLME of the DEV 1. A value obtained by adding‘mICRWT’ to ‘Instant CTB Duration’ should be smaller than ‘mAWT’ whichmeans the maximum waiting time. As the case may be, it may be set insuch a manner that the first message is transmitted and the secondmessage in response to the first message is received for the ‘InstantCTB duration.’ Also, like the example of FIG. 7, separate channelresources spaced apart from each other at a certain interval can beallocated for transmission of the first message and reception of thesecond message.

Hereinafter, the detailed embodiment to which the technical featuresaccording to the present invention have been applied will be described.In the embodiment which will be described hereinafter, the technicalfeatures of the present invention are applied to a method oftransmitting and receiving a message for interfacing a high-definitionmultimedia interface (HDMI) network which is a kind of a wire networkand a wireless video area network (WVAN) which is a kind of a wirelessnetwork (WPAN). In particular, the embodiment of the present inventionrelates to a method of transmitting a consumer electronics control (CEC)message from a specific device of the HDMI network to another device ofthe WVAN.

The HDMI is a multimedia interface which can transmit full digitalaudio/video data, which are not compressed. The HDMI provides a wireinterface between random audio/video devices such as set-top boxes, DVDplayers, monitors, and digital TVs. The HDMI supports multichanneldigital audio on a single cable along with improved high definitionvideo. In other words, it means that the HDMI can transmit every ATSCHDTV and also transmit eight-channel digital audio having a sufficientbandwidth. HDMI standard document, “High-Definition Multimedia InterfaceSpecification Version 1.2a, Dec. 14, 2005” can be referred to so as toobtain the detailed description of the HDMI.

FIG. 9 illustrates a schematic view according to the embodiment of thepresent invention. In FIG. 9, an HDMI device 40 and an interface device50 are connected with each other by a connector 45. The interface device50 receives A/V data streams and control information from the HDMIdevice 40 and transmits them to a specific device (not shown) of theWVAN through a wireless interface, so that the HDMI network is connectedwith the WVAN.

Referring to FIG. 9, the HDMI device 40 includes a main processor 41, anHDMI transmission chip 42, and a CEC signaling processor 43. Theinterface device 50 includes an HDMI reception chip 51, a formatconversion processor 52, a MAC/PHY entity 53, and an RF module 54. Audioand video data and their assistant data transmitted from the HDMItransmission chip 42 of the HDMI device 40 are transmitted to the HDIMreception chip 51 of the interface device through three TMDS channels.In FIG. 9, a video pixel clock is transmitted through a clock channel ofthe TMDS channel, and the HDMI reception chip 51 uses the video pixelclock as a frequency reference signals for data recovery on the threeTDMS data channels. The HDMI reception chip 51 forwards A/V streamstransmitted from the HDMI transmission chip 42 to the MAC/PHY entity 53.The format conversion processor 52 converts a format of controlinformation forwarded from the HDMI device 40 and forwards the convertedformat to the MAC/PHY entity 53. The MAC/PHY entity 53 processes thereceived data in accordance with a protocol, and the RF module 54performs wireless signal processing, such as wireless modulation,up-converting, and signal amplification, for the received data, andtransmits the processed data through an antenna (not shown).

FIG. 10A illustrates a data format of the CEC message used in the HDMIsystem. A CEC protocol provides a high-level control function betweenall kinds of visual devices under a user environment. Examples of mainCEC functions include one-touch play, system standby, one-touch record,and device menu control. The HDMI standard document, “High-DefinitionMultimedia Interface Specification Version 1.2a, Dec. 14, 2005” can bereferred to so as to obtain the details of the CEC functions.

Referring to FIG. 10A, an information bits field can include data,operation code, or address information. An end of message (EOM) bitindicates whether a corresponding bit corresponds to the end of amessage, and an acknowledgement (ACK) bit is used to indicate whether amessage receiving side has received data or header block. The ACK bit isset to ‘1’ by a source device which transmits the CEC message. If adestination device successfully receives the CEC message, ‘0’ istransmitted to the source device as an ACK signal.

FIG. 10B illustrates a data format of a header block. The header blockincludes EOM bit, ACK bit, an ‘Initiator’ field (source ID) foridentifying. the source device which has transmitted the CEC message,and a ‘Destination field’ (destination ID) for identifying a destinationdevice which should receive the CEC message. A starting bit is locatedat the front of the header block. The header block may be used as a‘Ping’ message for checking whether other devices are in an activestate.

FIG. 11 illustrates a pulse format of each bit constituting the CECmessage. In FIG 11, (a) is a pulse format of ‘0’ bit, and (b) is a pulseformat of ‘1’ bit. A pulse which expresses one bit has a length of 2.75ms.

FIG. 12A illustrates a structure of a system according to the embodimentof the present invention. In FIG. 12A, a source device 70 and adestination device 100 are interfaced with each other through a firstinterface device 80 and a second interface device 90. The firstinterface device 80 and the second interface device 100 may beimplemented physically to form a single body with the source device 70and the destination device 100, respectively. The first interface device80 and the second interface device 100 may physically be separated fromthe source device 70 and the destination device 100, respectively, andmay respectively be connected with the source device 70 and thedestination device 100 through a connector. The first interface device80 and the second interface device 100 perform communication through anair interface in accordance with WVAN protocol. The first interfacedevice 80 includes a CEC interface (I/F) module 81, an upper layerentity 82, and a MAC/PHY layer entity 83. The second interface device 90includes a CEC interface module 92, an upper layer entity 93, and aMAC/PHY layer entity 94.

FIG. 12B illustrates a structure of another system according to theembodiment of the present invention. The system according to theembodiment of FIG. 12B includes a source device 110, an interface device120, and a destination device 130. The system according to theembodiment of FIG. 12B is different from that of FIG. 12A in that asecond interface device (corresponding to 90 of FIG. 12A) has beenintegrated into the destination device 130. In other words, a processor131 of the destination device 130 implements the function of the CEC IFmodule 92 of the second interface device 90 in the system of FIG. 12A,and an upper layer entity 132 and a MAC/PHY entity of the destinationdevice 130 integrally implement the functions of the upper layer entity93 and the MAC/PHY entity 94 of the second interface device 90.

FIG. 13 is a flow chart illustrating a procedure according to theembodiment of the present invention. In the embodiment of FIG. 13, theCEC message is transmitted from a source device DEV A to a destinationdevice DEV B through the WVAN. The WVAN may include a coordinator, DEV1, DEV 2, and other devices. The DEV 1 and the DEV 2 are interfacedevices, and receive the CEC message from the DEV A and forward thereceived CEC message to the DEV B through the WVAN. The DEV 1 and theDEV 2 forward ACK, which is transmitted from the DEV 2 in response tothe CEC message, to the DEV A. To this end, the DEV 1 and the DEV 2include a CEC I/F module. In comparison with FIG. 12A, the DEV Acorresponds to the source device 70, the DEV B corresponds to thedestination device 100, and the DEV 1 and the DEV 2 correspond to thefirst interface device 80 and the second interface device 90,respectively.

Referring to FIG. 13, the DEV A performs signaling of the CEC message tothe CEC I/F module of the DEV 1 [S101˜S102]. If the DEV 1 receives theEOM bit of the CEC message, the DME of the DEV 2 forwardsMLME_INS_CTB.req primitive to the MAC/MLME of the DEV 1 to requestallocation of channel resources [S 103].

If the DEV 1 transmits a predetermined message, which includes the CECmessage, to the DEV 2, the DEV 2 requires resources to transmit aresponse message to the predetermined message, wherein the resourcesmean the channel resources. Since collision may occur if the DEV 2transmits the response message in accordance with a contention basedmethod without allocating separate channel resources, it is preferablethat the DEV 2 is allocated with channel resources in advance. It ispreferable that request and allocation of the channel resources areinstantly performed within a corresponding superframe in accordance withthe method described with reference to FIG. 7 or FIG. 8. In other words,if the channel resources are allocated in accordance with a generalmethod, an arrival time limit of ACK/NACK in response to the CEC messageof 2.75 ms may pass. Accordingly, allocation of channel resources isrequested from the DEV 1 within a corresponding superframe, and thecoordinator allocates channel resources, i.e., several unreserved CTBswithin the corresponding superframe.

The MAC/MLME of the DEV 1 transmits the instant channel resource requestmessage (INS_CTB_REQ Command) shown in Table 1 to the MAC/MLME of thecoordinator to request allocation of the channel resources [S104]. TheMAC/MLME of the coordinator forwards MLME_INS_CTB.ind primitive of thecoordinator to notify that the channel resources have been requestedfrom the DEV 1 [S105]. In response to the request of channel resources,the DME of the coordinator checks whether there are channel resources tobe allocated [S106].

If there are channel resources to be allocated, the DME of thecoordinator forwards MLME_INS_CTB.rsp primitive to the MAC/MLME of thecoordinator to command the MAC/MLME of the coordinator to transmitinformation of channel resources, which are to be allocated, to thedevices of the WVAN [S107]. The MAC/MLME of the coordinator broadcaststhe instant channel resource announcement message (INS_CTB_ANC Command)illustrated in Table 2 through the WVAN to notify the devices of theWVAN of information of the channel resources which are to be allocated[S108].

The MAC/MLME of the devices of the WVAN including the DEV 1 and the DEV2 forwards MLME_INS_CTB.cfm primitive to the DME to notify the fact ofallocation of the channel resources [S109, S110].

The DME of the DEV 1 forwards MLME_VD_CMD.req primitive to the MAC/MLMEof the DEV 1 to command the MAC/MLME of the DEV 1 to transmit the CECmessage to the DEV 2 [S111]. The MAC/MLME of the DEV 1 constitutes avendor specific request message (VD_CMD_REQ Command) which includes theCEC message, and broadcasts the vendor specific request message throughthe WVAN [S112]. Table 3 illustrates an example of a data format of thevendor specific request message.

TABLE 3 Octets: 1 1 3 n 0xFC Length = n + 3 Vendor OUI Vendor SpecificData

In table 3, a ‘Vendor OUI’ field includes information of vendor OUI(Organizational Unique Identifier) information, and a ‘VendorSpecification Data’ field includes a message which is to be forwarded,i.e., the CEC message in FIG. 13. The ‘Vendor Specification Data’ fieldmay include a message or control information, which is not defined inWiHD standard document. At this time, data may be included in the‘Vendor Specification Data’ byte unit. For example, the CEC messageincludes 1 byte from bit 7 to bit 0, and then may additionally includebit information indicating EOM.

As another embodiment, the MAC/MLME of the DEV 1 can directly broadcastthe message or control information, which is not defined by the WiHDstandard document, i.e., the CEC message through the WVAN withoutincluding the message in the vendor specific request message (VD_CMD_REQCommand). In this case, a packet may be constituted in a byte unit andthen broadcasted.

The MAC/MLME of the DEV 2 forwards MLME_VD_CMD.ind primitive to the DMEof the DEV 2 to notify that the vendor specific request message has beenreceived [S113].

The CEC I/F module of the DEV 2 starts signaling of the CEC messageincluded in the vendor specific request message to forward the CECmessage to HDMI devices connected with the DEV 2 [S114]. The DEV 2performs an address resolution procedure after starting signaling of theCEC message [S115]. In other words, the DEV 2 checks, through theaddress resolution procedure, whether there is a destination device,i.e., DEV B, to which the CEC message is to be forwarded, among the HDMIdevices connected with the DEV 2.

If the DME of the DEV 2 checks, through the address resolutionprocedure, that the DEV B has been connected with the DEV 2, the DEV 2transmits ACK signal to the CEC message to the DEV 1 even before endingsignaling of the CEC message. In other words, the MAC/MLME of the DEV 2constitutes the vendor specific request response message (VD_CMD_RSPCommand) which includes ACK in response to the CEC message, andtransmits the vendor specific request response message to the DEV 1[S117]. Table 4 illustrates an example of a data format of the vendorspecific request response message.

TABLE 4 Octets: 1 1 3 1 0xFD Length = 4 Vendor OUI Error Reason Code

If the DME of the DEV 2 identifies, through the address resolutionprocedure, that the DEV B has not been connected with the DEV 2, the DMEmay end forwarding of the CEC message.

The vendor specific request response message is transmitted through thechannel resources allocated in the steps S104˜S108 for allocation of thechannel resources. The MAC/MLME of the DEV 1 forwards MLME_VD_CMD.cfmprimitive to the DME of the DEV 1 to notify the fact that the vendorspecific request response message has been received [S118]. The CEC I/Fmodule of the DEV 1 transmits ACK to the DEV A based on the vendorspecific request response message [S119].

After receiving the EOM bit of the CEC message [S120], the DEV Btransmits ACK or NACK to the DEV 2 depending on the presence ofreceiving error [S121]. If the DEV 2 receives ACK from the DEV B,transmission of the CEC message ends. However, if the DEV 2 receivesNACK, the DEV 2 should re-transmit the CEC message to the DEV B.

In FIG. 13, ‘mICRWT’ means a maximum Instant CTB Request Waiting Time,and ‘Instant CTB Duration’ means a waiting time set such that the DME ofthe DEV 1 forwards MLME_VDCMD.req primitive to the MAC/MLME of the DEV 1and receives MLME_VD_CMD.cfm primitive from the MAC/MLME of the DEV 1. Avalue obtained by adding ‘mICRWT’ to ‘Instant CTB Duration’ should besmaller than ‘mAWT’ which means the maximum ACK/NACK waiting time. TheCEC message has ‘mAWT’ of 2.75 ms.

Terminologies used herein may be replaced with other terminologies. Forexample, the device may be replaced with a user device (or apparatus) orstation, the coordinator may be replaced with a coordinating apparatus(or control apparatus), a coordinating device (or control device), acoordinating station (or control station), or piconet coordinator (PNC).

The aforementioned embodiments are achieved by combination of structuralelements and features of the present invention in a predetermined type.Each of the structural elements or features should be consideredselectively unless specified separately. Each of the structural elementsor features may be carried out without being combined with otherstructural elements or features. Also, some structural elements and/orfeatures may be combined with one another to constitute the embodimentsof the present invention. The order of operations described in theembodiments of the present invention may be changed. Some structuralelements or features of one embodiment may be included in anotherembodiment, or may be replaced with corresponding structural elements orfeatures of another embodiment. Moreover, it will be apparent that someclaims referring to specific claims may be combined with another claimsreferring to the other claims other than the specific claims toconstitute the embodiment or add new claims by means of amendment afterthe application is filed.

The embodiments according to the present invention may be implemented byvarious means, for example, hardware, firmware, software, or theircombination. If the embodiment according to the present invention isimplemented by hardware, it may be implemented by one or moreapplication specific integrated circuits (ASICs), digital signalprocessors (DSPs), digital signal processing devices (DSPDs),programmable logic devices (PLDs), field programmable gate arrays(FPGAs), processors, controllers, microcontrollers, microprocessors,etc.

If the embodiment according to the present invention is implemented byfirmware or software, it may be implemented by a type of a module, aprocedure, or a function, which performs functions or operationsdescribed as above. A software code may be stored in a memory unit andthen may be driven by a processor. The memory unit may be located insideor outside the processor to transmit and receive data to and from theprocessor through various means which are well known.

According to the present invention, the following advantages can beobtained.

First of all, it is possible to instantly allocate the channel resourcesif necessary even under the circumstances that the channel resources arealready allocated.

In addition, delay in message transmission between the wire network andthe wireless network or between two devices can be avoided, wherebydesirable communication can be performed.

It will be apparent to those skilled in the art that the presentinvention can be embodied in other specific forms without departing fromthe spirit and essential characteristics of the invention. Thus, theabove embodiments are to be considered in all respects as illustrativeand not restrictive. The scope of the invention should be determined byreasonable interpretation of the appended claims and all change whichcomes within the equivalent scope of the invention are included in thescope of the invention.

INDUSTRIAL APPLICABILITY

The present invention is applicable to a wireless network system.

What is claimed is:
 1. A device for allocating a channel resource in awireless network, the device comprising: a Media Access Control(MAC)/MAC Layer Management Entity (MLME) sublayer which is adapted to:receive a primitive requesting to transmit a message for requesting thechannel resource from an upper layer; transmit the message forrequesting the channel resource to a coordinator, wherein the channelresource is to be used for both transmitting a first message to a seconddevice and receiving a second message from the second device in responseto the first message, wherein the message for requesting the channelresource includes information about a duration of the channel resource;and receive channel resource allocation information for allocating thechannel resource from a MAC/MLME sublayer of the coordinator, whereinthe channel resource allocation information comprises information abouta duration of the allocated channel resource, wherein the devicetransmits the first message to the second device during the channelresource allocated based upon the channel resource allocationinformation, and wherein the device receives the second message from thesecond device in response to the first message during the allocatedchannel resource,
 2. The device of claim 1, wherein the device receivesthe channel resource allocation information for allocating the channelresource that is broadcasted by the coordinator in response to themessage for requesting the channel resource.
 3. The device of claim 1,wherein the message for requesting the channel resource is not the sameas the first message.
 4. The device of claim 1, wherein the message forrequesting the channel resource comprises identifiers of the device andthe second device.
 5. A coordinator for allocating a channel resource ina wireless network, the coordinator comprising: a Media Access Control(MAC)/MAC Layer Management Entity (MLME) sublayer adapted to: receive amessage for requesting the channel resource from a MAC/MLME sublayer ofa first device, wherein the message for requesting the channel resourceincludes information about a duration of the channel resource, andwherein the MAC/MLME sublayer of the first device receives a primitiverequesting to transmit the message for requesting the channel resourcefrom an upper sublayer of the first device; and broadcast channelresource allocation information for allocating the channel resource,wherein the channel resource allocation information comprisesinformation about a duration of the allocated channel resource, whereinthe channel resource is to be used by the first device for bothtransmitting a first message to a second device and receiving a secondmessage from the second device in response to the first message.
 6. Thecoordinator of claim 5, wherein the first device receives the channelresource allocation information for allocating the channel resource thatis broadcasted by the coordinator in response to the message forrequesting the channel resource.
 7. The coordinator of claim 5, whereinthe message for requesting the channel resource is not the same as thefirst message.
 8. The coordinator of claim 5, wherein the message forrequesting the channel resource comprises identifiers of the firstdevice and the second device.